Using state laws prohibiting "unlawful paramilitary activity" and private citizens from falsely posing as law enforcement, the new lawsuit was filed against more than more than 20 individuals, self-described militia groups, and white nationalist organizations, including several leaders of the "Unite the Right" rally back in August.

Charlottesville and city officials file a lawsuit Thursday to prevent 'private militia' groups.

"Whatever their stated intentions, these groups terrified local residents and caused attendees to mistake them for authorized military personnel," wrote attorneys for the city in the complaint. "It was in Charlottesville that an online clique of ethno-statists became a movement with real destructive force -- that they began 'stepping off the internet in a big way.'"

The Charlottesville City Council voted in open session Thursday morning to join the suit, now alongside dozens of local businesses and neighborhood associations. The suit could potentially serve as a template for future legal action as other local officials struggle to contain private militia groups rallying in other cities across the country.

Hours of video footage captured men at a Friday night rally in August with Tiki torches marching onto the University of Virginia's campus screaming, "Jews will not replace us!" Later Saturday, men with firearms, batons and riot shields wearing combat boots, military-grade body armor, and camouflage uniforms descended upon the city.

"We thought the law should have a response to this and it does," said Mary McCord, a longtime federal prosecutor who is now part of the newly formed Georgetown Law Institute for Constitutional Advocacy and Protection leading Thursday's lawsuit.

"This was a conscious strategy of 'provoke and invoke,'" said Joshua Geltzer, a former national security lawyer at the Justice Department and now executive director of the institute. "Those who came to Charlottesville looking for a fight planned to use paramilitary tactics to provoke violence on the part of counter-protestors and bystanders, then to invoke self-defense as an excuse for the violence they intended all along."

McCord emphasized to the city council that the lawsuit is not aimed at infringing upon free speech rights to protest or second amendment rights to self-defense. The suit is also not seeking any money damages, but rather only a court order to stop future private military action.

"In Charlottesville today, as through centuries of American tradition, the government alone retains a monopoly on the organized use of force," attorneys further argued in the complaint.

Attorney General Jeff Sessions vowed that the Justice Department will "take the most vigorous action" to protect Americans against "racism and bigotry" in the aftermath of the tragedy in Charlottesville, but legal experts have noted the challenges of using federal civil rights statutes in this case given the burden of proof.